Unlike many other docks, this charger makes use of the standard micro usb port on the back of the controller. Whilst this means you have to have a mini adapter in the back of the controller, it makes it soooo much easier to dock the controller. The shape of the cradle ensures the connectors line up properly and you don't have to faff around getting the controller to plug into the front charger port each time.
Personally I think the adaptors could have been designed to look a little nicer in the back of the controller, but realistically they are barely noticeable and don't get in the way. It's also nice that they provide spares, so you can either have them in 4 controllers (2 in use, 2 on charge) or keep them in case you lose one at some point.
Main reason I dropped a star is because the lights on the dock are always on - green if fully charged/empty and red when charging. I find them quite bright and I imagine would be distracting in a dark room. It would have been much nicer if they only lit up when something was docked. If I could rate it 4.5/5 I would.